1. Field of the Invention
The present invention is directed to an active suspension system for a tracked vehicle.
2. Description of the Prior Art
Tracks provide vehicles with high floatation in soft field conditions. Steel tracks are by far the most common tracks and comprise an endless chain on which track shoes are mounted. The endless chain engages a main drive wheel sprocket which drives the chain and propels the tracks and vehicle. Belted tracks are also available. One belted track system uses highly tensioned belted tracks. In another belted track system, the tracks are provided with apertures. The apertures engage a main drive sprocket wheel for driving the tracks and propelling the vehicle. A third belted track system uses a specialized main drive wheel to engage centering guide lugs for driving the track.
Various suspension systems for crawlers have also been developed. Track rollers help distribute the load of the vehicle on the track. In a rigid suspension system, the track rollers are directly mounted to the track frame. Loads imparted to the track rollers are directly transferred to the track frame. In an active suspension system, the track frame is provided with a means for dampening the loads imparted to the track rollers which more evenly distributes the load as the tracks encounter obstacles (See U.S. Pat. No. 4,339,156, 4,361,363, 4,373,758 and 4,519,654).
High drive crawlers having an elevated main drive wheel are well known (See U.S. Pat. No. 4,373,758). In addition track technology has been applied to all sorts of agricultural vehicles. For example tractors, grain carts and agricultural combines. It is known to equip agricultural combines used in harvesting rice with half tracks to provide better floatation (See PCT WO 90/05996).